Machine element



Aug. 9, 1966 s. A. BULlN MACHINE ELEMENT 2 Sheets-Sheet 1 Filed June 5, 1963 INVENTOR.

W, m 70 M w w A IWM Y L 4 w 5 S. A. BULIN MACHINE ELEMENT Aug. 9, 1966 Filed June 5, 1963' 2 Sheets-Sheet 2 INVENTOR. 5/154 ALBERT Buu/y BY 5% g H TTGRNEY United States Patent 3,265,451 MACHINE ELEMENT Shelley Albert Bulin, Davenport, Iowa, assignor to J. I. Case Company, Racine, Wis. Filed June 5, 1963, Ser. No. 285,710 3 Claims. (Cl. 3088) The present invention relates to machine elements and particularly to a journal bearing construction primarily for radial loading wherein it is desirable to keep the cost as reasonable as possible, consistent with good or superior reliability. Particularly, it relates to bearings for mounting straw walkers on crankshafts as used in threshing mechanism, and therefore ,relates particularly rto the crankpin portions and an object of the invention is to generally improve the construction 0nd operation of devices 'of this class.

Prior constructions used for this purpose have left something to be desired, and the principal object of the present invention is to supply such a journal bearing which will have superior reliability and quality and which at the same time can be produced at substantially less cost than prior arrangements.

Such crankshafts in the past have been formed by bending a rough rod or sh-aft into a plurality of offset journal or crankpin portions and then machining, grinding, or otherwise finishing the journal portions to a suitable polished bearing surface. The bearing itself to be run on this surface took the form of a block of hard wood which had been soaked or boiled in oil or suitable lubricant and which would run on the polished surface in supporting relation for long periods without attention. However, such bearings had a tendency to wander down the bent portions of the shaft which extended between the individual journals, and to stop this action, washers were welded to the shaft or otherwise fixed thereon at the ends of the finished portions so as to engage the ends of the wood blocks and prevent their displacement axially of the journals. Such operation tended to be costly, and it was not always possible to maintain proper tolerances as to dimensions. Furthermore, it was difilcult to maintain the washers square or at right angles to the journals. These difiicul'ties were increased by the fact that the shaft was rough in the regions away from the actual finished journals, and it was to this rough portion that the washers Were welded or otherwise fixed. In addition, the heating of the shaft in order to weld the washers in place could tend to cause undesirable warping of the shaft so that the finished article would either have to be discarded or would require straightening operations before it would be acceptable. By the present invention, these difficulties are avoided and a device is provided which is of superior quality and reliability.

The construction and features of a preferred embodiment of the invention are set forth in the following specification and illustrated in the accompanying drawings, in which:

FIG. 1 is a transverse vertical sectional view with parts omitted showing a fragment of the separator portion of a typical combine or threshing machine in which the invention is used.

FIG. 2 is a sectional view of a fragment of the same, taken on the line 22 of FIG. 1.

FIG. 3 is an enlarged vertical axial sectional view of one of the bearings, taken on the line 33 of FIG. 2.

FIG. 4 is a vertical sectional view with parts broken away, taken on the line 4-4 of FIG. 3.

Similar reference characters have been applied to the same parts wherever they occur throughout the specification and drawings.

Turning to FIGS. 1 and 2, the illustrative machine 3,265,451 Patented August 9, I966 comprises a housing 10 which supports a bearing construction generally designated as 12, which supports the crankshaft generally designated as 14, in position to operate in the machine. The crankshaft commonly comprises a rough steel or other bar which is bent in various directions to give the necessary or desired crank throws. This results in a plurality of offset journal or crankpin portions, one of which is shown in detail in FIG. 3, and generally designated 16, and which crankpin portions have machined, ground, or otherwise finished journal portions which are held to a degree of accuracy suflicient to operate in a satisfactory manner and are suitable to carry the load imposed on the bearing construction.

Crankshaft 14, as stated, is carried in bearing 12 and a companion bearing not shown, and is driven by a belt 18 actuated from any convenient moving part of the threshing mechanism. Belt 18 drives a pulley 20 suitably fixed on shaft 14, and which therefore causes shaft 14 to rotate.

The bearings cooperating with journals 16 in the illustrative machine are split wood blocks 22, each comprising a base portion 24 and a cap portion 26. Portions 24 and 26 are secured to each other by means of bolts 28 and 30, which also engage the bottom wall 32 of a unit commonly known as a straw walker 34, thus securing the bearing 22 rigidly on the straw walker 34. Straw walker 34 is elongated and is supported adjacent one end by bearing 22, the unit being given a revolving movement, at least at such end by its support on the rotating crankshaft 14. In the threshing mechanism, it supports the t-hreshed straw and tends to agitate it and propel it toward the exit end of :the machine. For this purpose, it is provided with a plurality of teeth 36, FIG. 2, and other features which do not relate to the present invention, and therefore need not be further described.

The improved journal bearing is shown in more detail in FIGS. 3 and 4. The crankshaft is formed from a rough steel or other rod or shaft and presents a plurality of bent portions as 38 which do not need to be finished, but which connect the several journal or crankpin portions which are ofifset from each other as aforesaid. By machining, grinding or otherwise finishing, crankpin portions 16 are provided with reduced load carrying journal portions 40, 42, 44, 46 and 48, which are spaced axially of crankpin 16 and separated by lands 50, 52, 54 and 56 respectively. Forming reduced journal portion 40, at the same time produces a wall or shoulder 58 between bent portion 38 and portion 40. It also produces a wall or shoulder 60 between portion 40 and land 50. In similar manner, producing reduced portion 42, at the same time produces a shoulder 62 between it, and land 50 and a shoulder 64 between it and land 52. In similar manner, shoulders 66 and 68 are formed at the ends of reduced portion 44; 70 and 72 at the ends of reduced portion 46, and shoulders 74 and 76 at the ends of reduced portion 48. It is to be noted that the grinding or other machining of reduced portions 40 thru 48 will readily also finish or machine the several walls or shoulders 58 thru 76. Furthermore, any reasonable inaccuracies in the location of the crankpin portions, by reason of the comparatively rough bending operation of the original rod will be corrected in the machining process by reason of the usual chucking procedure. Thus, while reduced portions 40 thru 48 can be readily made to run true by well-known machining processes, the tolerances or permissible inaccuracies of the outer surfaces of bent portions 38 and lands 50 thru 56 can be quite liberal for reasons which will appear.

Base portion 24 and cap portion 26 of bearing 22 are so formed that they form, when they are clamped together by bolts 28 and 30, a bore which is of a size to have a running fit on journals 40 thru 48 of crankpin 16, the whole being of a length to form a running fit with shoulders 58 and 76. Furthermore, this bore which may be generally designated as 78 is enlarged at intervals to provide grooves of a size and location to receive lands 50, 52, 54 and 56. The grooves are designated as 80, 82, 84 and 86 and are formed of a width to provide a suitable running fit with their associated shoulders. Thus, groove 80 will engage shoulders 60 and 62 and groove 84 will engage shoulders 68 and 70.

As stated, the several shoulders will be made smooth by the machining process and will therefore present suitable bearing surfaces to the walls of the grooves. The grooves are preferably formed deeper than the height of the land 50, 52, etc., so that the grooves will clear the outer peripheral surfaces of the lands, as clearly shown in FIG. 4. Thus, it is not necessary that the outer surfaces of the lands be exactly concentric with the reduced portions of journal 16 with which they are associated, since the rough peripheral surfaces of the lands will not contact such peripheral surfaces at any time. The walls of the grooves run in contact or in running relation to the walls or shoulders of the lands, and preferably also in contact with the shoulders formed between the endmost reduced portions and the remaining rough portions of the shaft. This results in a relatively large number of shoulders to resist the end thrust set up by any tendency of the bearing 22 to travel along the length of the crankshaft and in view of the large number of shoulders (5 in the illustrative example), the shoulders need not be very high in order to otfer ample surface to resist the thrust involved which, as well understood, is only a small fraction of the load carried by the assembly. In forming the lands 50 thru 56, it is therefore not necessary to reduce the original diameter of the rough shaft to any substantial extent in order to form the reduced portions 40 thru 48, and thus the shaft is not appreciably weakened by the machining necessary to produce the journal surfaces 40, 42, etc., and the lands 50 thru 56.

By virtue of the invention, it is possible to provide a journal bearing primarily for radial loads, but furnishing a relatively large number of thrust surfaces to resist end play, and which bearing may be made with a minimum of operations and such operations as will largely eliminate the possibility of human error.

While the invention has been illustrated in connection with a crankshaft and a straw walker bearing for a threshing apparatus, as well as a type of bearing comprising a wood block running on a steel shaft, the arrangement might be used in connection with journal bearings for other purposes, as for example, bearings for supporting rotary shafts in any machinery where low cost with a high degree of reliability is important. Furthermore, the hearing may be made of other materials than wood, many of the advantages being characteristic of the structure regardless of the material used, and it is not intended that the invention shall be taken as limited to a straw walker bearing, to a wood hearing, or in fact in any manner beyond the requirements of the claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a bearing for use in supporting a straw walker in a threshing mechanism, the combination of a crankshaft, a crankpin portion radially offset from said crankshaft, said crankpin portion having a plurality of axially spaced reduced load carrying journal portions providing lands therebetween of a diameter greater than said reduced portions, and a bearing element disposed about said crankpin portion in supporting and running contact with said reduced portions, and said bearing element comprising a wood block fixed to said straw walker and providing a plurality of internal grooves disposed about said lands, the Walls of said grooves being engaged in running contact with the walls of said lands to secure said bearing element against movement axially of said journal portion.

2. In a bearing for use in supporting a straw walker in a threshing mechanism, the combination of a crankshaft, a crankpin portion radially offset from said crankshaft, said offset crankpin portion having a plurality of axially spaced finished reduced journal portions providing finished wall lands therebetween of a diameter greater than said reduced journal portions, and a bearing element comprising a wood block fixed on said straw walker and disposed about said journal portion in running and supporting contact with said reduced journal portions, and said bearing element providing a plurality of grooves disposed about said lands, the walls of said grooves being engaged in running contact with the finished walls of said lands to secure said wood block against movement axially of said journal portion, and said grooves being of a depth to provide clearance in said wood block about the peripheries of said lands.

3. A crankshaft bearing assembly for use in a threshing mechanism for supporting a straw walker therein, said crankshaft comprising a rough surfaced shaft of uniform diameter having the characteristics of a shaft that has been bent to provide a plurality of offset crankpin portions, each crankpin portion providing a plurality of finished reduced journal portions spaced axially along said crankpin portion and providing lands therebetween projecting from said reduced journal portions, said lands having the diameter of the original rough shaft, and a bearing element comprising a wood block fixed on said straw walker and disposed about said crankpin portion in running and supporting contact with said reduced journal portions, said bearing element providing a plurality of grooves disposed about said lands, the walls of said grooves being engaged in running contact with the finished walls of said lands to secure said wood block against movement axially of said crankpin portion, and said grooves being of a depth to provide clearance in said wood block about the rough peripheral surfaces of said lands.

References Cited by the Examiner UNITED STATES PATENTS 388,227 8/1888 Smith 308-162 555,109 2/1896 McGarry 308162 563,134 6/1896 Campbell 308162 809,392 1/1906 OReilly 308-161 1,020,745 3/1912 Debes 308-162 1,126,071 1/1915 Peter 308-162 X 1,309,763 7/1919 McKennitt 308-162 1,733,910 10/ 1929 Sehmisch 74-595 1,971,433 8/1934 Tartrais 29149.5 2,415,324 2/ 1947 Wilson 29149.5 2,937,647 5/ 1960 Allen '-26 FOREIGN PATENTS 333,417 2/1921 Germany.

7 DAVID J. WILLIAMOWSKY, Primary Examiner.

FRANK SUSKO, DON A. WAITE, Examiners.

L. L. JOHNSON, Assistant Examiner. 

3. A CRANKSHAFT BEARING ASSEMBLY FOR USE IN A THRESHING MESCHANISM FOR SUPPORTING A STRAW WALKER THEEIN, SAID CRANKSHAFT COMPRISING A ROUGH SURFACED SHAFT OF UNIFORM DIAMETER HAVING THE CHARACTERISTICS OF A SHAFT THAT HAS BEEN BENT TO PROVIDE A PLURALITY OF OFFSET CRANKPIN PORTIONS, EACH CRANKPIN PORTION PROVIDING A PLURALITY OF FINISHED REDUCED JOURNAL PORTIONS SPACED AXIALLY ALONG SAID CRANKPIN PORTION AND PROVIDING LANDS THEREBETWEEN PROJECTING FROM SAID REDUCED JOURNAL PORTIONS, SAID LANDS HAVING THE DIAMETER OF THE ORIGINAL ROUGH SHAFT, AND A BEARING ELEMENT COMPRISING A WOOD BLOCK FIXED ON SAID STRAW WALKER AND DISPOSED ABOUT SAID CRANKPIN PORTION IN RUNNING AND SUPPORTING CONTACT WITH SAID REDUCED JOURNAL PORTIONS, SAID BEARING ELEMENT PROVIDING A PLURALITY OF GROOVES DISPOSED ABOUT AND LANDS, THE WALLS OF SAID GROOVES BEING ENGAGED IN RUNNING CONTACT WITH THE FINISHED WALLS OF SAID LANDS TO SECURE SAID WOOD BLOCK AGAINST MOVEMENT AXIALLY OF SAID CRANKPIN PORTION, AND SAID GROOVES BEING OF A DEPTH TO PROVIDE CLEARANCE IN SAID WOOD BLOCK ABOUT THE ROUGH PERIPHERAL SURFACES OF SAID LANDS. 